Method of producing a composite with an absorbent layer

ABSTRACT

The present invention relates to a multilayer product having at least one first layer, an absorbent intermediate layer and a second layer, whereby at least the first layer contains at least one first material and one second material. The first layer and/or the second layer is at least partially liquid permeable. The first material has a higher melting point than the second material, with the second material creating a bond to the second layer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No.10/501,601, filed Jan. 27, 2005; which is a 37 U.S.C. 371 National Phasefiling of PCT International Application No. PCT/EP03/00635, filed Jan.23, 2003; which claims priority from German Application DE2002010205828filed Feb. 13, 2002, the priority of which applications are claimed.

FIELD AND BACKGROUND OF THE INVENTION

The present invention relates to a multilayer product comprising atleast one first layer, an absorbent intermediate layer and a secondlayer. The first layer contains at least one first material and onesecond material, whereby the first and/or second layer is at leastpartially liquid-permeable.

World International Patent 95/03019 describes the production of amultilayer product, whereby an absorbent material is arranged between atop layer and a bottom layer. The absorbent material is applied asstrips, with an adhesive being applied between the strips in the machinedirection. The adhesive causes the top layer and the bottom layer to bebonded together. Therefore, the absorbent material is to be sealed atthe sides. European Patent 0 846 455 A1 also describes the production ofa multilayer product. In this case again, lateral strips of adhesive areapplied to the substrate to subsequently bond a top layer to it. Inaddition to sealing in the machine direction, sealing in the transversedirection is achieved by supplying an additional top layer and bottomlayer to the three-layer product. The additional sealing is achieved byapplying a thermoplastic material and then heating until at leastreaching the softening point. In this way, the absorbent material ismore or less baked to the adjacent top layer and bottom layer. It isknown from WO 97/07761 to use a nonwoven material which should enclosean absorbent layer. This nonwoven should be especially dense incomparison with the absorbent material because of its properties. WO01/39707 also describes the production of a multilayer product which hasan absorbent material between a top layer and a bottom layer. The toplayer is liquid-permeable and should be a nonwoven, a film, a compositematerial or the like. The bottom layer should preferably have aspunbonded nonwoven and a meltblown nonwoven. Due to the design of thebottom layer, this should achieve the result that losses of absorbentmaterial in a subsequent further processing of a multilayer product areminor.

SUMMARY OF THE INVENTION

The object of the present invention is to create a multilayer product,which will further prevent loss of material arranged between the layers.

This is achieved with a multilayer product having the features of Claim1 as well as with a method having the features of Claim 15. Otheradvantageous embodiments are characterized in the respective dependentclaims.

A multilayer product having at least one first layer, an activeintermediate layer, preferably absorbent, and a second layer, whereby atleast the first layer has at least one first material and one secondmaterial, and the first layer and/or the second layer is at leastpartially liquid-permeable, has a higher melting point for the firstmaterial than for the second material. The second material creates abond with the second layer. The second material serves in particular topermit a seal between the first layer and the second layer. Thispreferably makes it possible to omit an additional adhesive. The meltingpoint of the second material is preferably so far from the melting pointof the first material that reaching the softening point of the secondmaterial does not result in the first material losing its shape and/orsoftening itself. The softening temperatures of the two materials arepreferably separated by a difference of at least 5° C., preferably atleast 10° C. It has proven advantageous if the softening point of thesecond material is in a range of between 10° C. and 15° C., preferably20° C. from the softening point of the first material. For example, ifpolyethylene, which has a softening point of approximately 120° C. toapproximately 130° C., and polypropylene, which has a softening point ofapproximately 160° C. to approximately 170° C., are processed together,their softening temperatures can be adapted accordingly throughappropriate addition of suitable additives to increase or reduce thesoftening temperature accordingly. When using the property of softeningof the second material, a surface property of same which permits bondingbetween the first layer and the second layer for the first time ispreferably utilized. On reaching the softening temperature, according toone embodiment, the second material should become tacky and inparticular should be readily deformable.

According to another embodiment, the second material should have amelting point which has a temperature difference of at least 3° C.,preferably at least 8° C., from the melting point of the first material.According to a refinement, the melting point of the second material issuch that the softening point of the first material is beneath it.

According to one embodiment, the first layer has first fibers whichcontain the first material and second fibers which contain the secondmaterial. This makes it possible first to use a fiber composite toproduce the first layer. Secondly, heating the first layer allows thefiber structure of the second material to be preserved, while the fiberstructure of the second material is used for sealing and bonding thefirst layer to the second layer. In particular, the use of fibers makesit possible to achieve a completely tight fusion between the first layerand the second layer due to the juxtaposition thereof and softening andin particular at least partial melting of the fibers. As a result ofthis fusion of the two layers, an absorbent material can no longerescape through this bonding site.

According to another embodiment, the multilayer product has a firstlayer with first fibers, which contain the first material as well assecond fibers containing the first material and the second material. Thesecond fibers are preferably bicomponent fibers, whereby the firstmaterial is preferably arranged in a core while the second materialextends as a sheath around this core. Another possibility is for fibercross-sections of the bicomponent fiber to each have a differentmaterial.

According to another embodiment, the second material is in contact withthe intermediate layer. This advantageously results in the intermediatelayer also adhering to the second material in the contact area, if thisarea is heated accordingly. This leads to immobilization of theabsorbent material of the intermediate layer. In addition, this alsoachieves the result that the absorbent material in this area itselfforms a barrier through which it is extremely difficult for theabsorbent material above it to penetrate.

For example, an absorbent fiber and/or an absorbent powder is used forthe absorbent intermediate layer. There is also the possibility of usinga gel, granules or the like. In addition, there is also the possibilityof using mixtures of material. The absorbent intermediate layer may alsobe provided with an additional material having other functions than thatof absorption. For example, the additional material may result in aspecial strength, stiffness or the like.

According to another embodiment, the second material has a non-positiveconnection with the second layer. A non-positive connection in thissense means, for example, that the second material is chemically and/orphysically bonded to the second layer and/or penetrates into the secondlayer, if not actually permeating through it. After solidification ofthe second material, this ensures that the bond thus created can besevered only by applying a force. According to another embodiment, thesecond material seals the intermediate layer at the sides in cooperationwith the second layer. The second material preferably seals theintermediate layer all the way around.

Preferably only the second material of the first layer is in contactwith the second layer. This makes it possible, for example, for thefirst material of the first layer to have a special task or a specialfunction. For example, it may be designed to be especially hydrophilic,while the second material is less hydrophilic. If a liquid bridge iscreated between the first layer and the absorbent material, the latterabsorbs the liquid, with the second layer ensuring, because of the lowerhydrophilic property, that there will be an interruption in the suctionflow thus created. On the other hand, a greater hydrophilic property ofthe second material in comparison with that of the first material canensure that there will be an increased capacity to absorb liquid to theabsorbent material of the intermediate layer by means of the gradientthus formed.

It has also proven advantageous if the multilayer product is designed sothat the second layer also contains the second material of the firstlayer. This permits an especially tight bond between the first layer andthe second layer, in that preferably both materials are heated toapproximately same temperature and preferably are at least softened. Inparticular, both materials can be heated to the extent that they flowinto one another and thus yield a type of welding. This is especiallyadvantageous inasmuch as it yields high strength values especially withrespect to transverse forces and tensile forces. According to anotherembodiment, the multilayer product has a first layer, which containsessentially a high-melting polymer, e. g. polypropylene, as the firstmaterial and a low melting polymer, e.g., polyethylene, as the secondmaterial. The polyethylene has, for example, a melting point between106° C. and 155° C., while the polypropylene has a higher melting point.

One area of application of the multilayer product is to use it in ahygiene article to absorb a fluid. In addition, the multilayer productmay also be used in household applications or other areas where a liquidor some other fluid is to be absorbed. In particular, the multilayerproduct can be used to influence an odor in the environment. Forexample, odors that are perceived as unpleasant can be absorbed andstored by the product, e. g., by binding them or otherwise neutralizingthem.

According to another example of this invention, a method of producing amultilayer product having at least one first layer, an absorbentintermediate layer and a second layer is created. At least the firstlayer has at least one first material and one second material, the firstlayer and/or the second layer being at least partially liquid-permeable.

A first material which has a higher melting point than the secondmaterial is used, whereby the second material is heated at leastapproximately up to its melting point, and the first layer and thesecond layer are bonded together by means of the heated second material.

According to another embodiment, a powder is applied to the secondmaterial to form the absorbent intermediate layer at least in partbefore the second material is heated, whereby the powder is at leastpartially bonded to the second material. In particular, the secondmaterial is heated until the intermediate layer is sealed at the sides.

According to another embodiment, the multilayer product is punched outof a sheeting which is supplied continuously. The contours of themultilayer product are preferably arranged so they are offset from oneanother on the sheeting thus supplied, so that waste of sheetingmaterial left over is minimal.

Examples of embodiments of this invention are given below, theirfeatures being combinable with one another to form advantageousrefinements.

The multilayer product is used, for example, to introduce a powder, e.g., SAP, into cellulose (fluff) preferably for hygiene applications, inparticular as absorbent layers for diapers, to keep one or more activepowders, e. g., in a three-dimensional fiber structure, in place in themultilayer product, to secure a mixture of fibers and powder and/oranother absorbent material in a desired geometric shape and/or to holdSAP fibers, for example, in and/or between airlaid materials ornonwovens. For example, a hot adhesive powder, e. g. PE or EVA powder orfibers may be used in addition as a fixation aid, leading to bonding ofsurrounding fibers and/or grains of powders because of the heating ofthe multilayer product.

An example of a multilayer product is described in greater detail below.The product has a first outer layer. The first outer layer may includethermoplastic fiber layers, a film and/or a nonwoven. They preferablyhave a first component or a first layer of a homopolymer which has ahigher melting point, e. g., polypropylene. This has the advantage thatit yields a good processing property, especially with respect toprocessing under the influence of heat, where a high strength isretained. In particular, this prevents sticking to guide rollers or thelike. A second component and/or a second layer has in part a low meltingpoint in comparison with the first layer and/or component. For example,a bicomponent fiber is used. The bicomponent fiber is preferablydesigned as a side-by-side structure or as a core-sheath structure, inparticular made of a mixture of material containing polypropylene and/orpolyethylene. According to another embodiment, the second componentand/or the second layer has a low melting part, e. g., a polyethylene.This is used to achieve a rapid melting under the influence of heat, andthus to achieve adhesion to the powder. The part, such as apolypropylene, which does not melt until reaching high temperatures thenensures a tight bond of the second layer and/or component with the firstlayer and/or component. An intermediate layer, preferably containingactive particles, is connected to the components. These may be, inparticular, SAP, zeolites, activated carbon, odor and liquid absorbers,pH indicators and/or regulators, coloring agents, complexing agents EDTA(ethylenediamine tetraacetate), aroma or flavoring substances. Theparticles preferably have a certain particle size distribution, so thereis no leakage of particles through the corresponding surrounding layers.

According to another embodiment, the particle size distribution isdesigned so that finer particles are preferably surrounded by somewhatlarger particles. In particular, the larger particles may form a barrierto prevent the escape of the finer particles toward the outside throughthe surrounding layers and vice versa. A second outer layer is situatedadjacent to the intermediate layer. This second outer layer preferablyhas the same fiber layer as the first outer layer. In particular alow-melting part of the second outer layer is situated so it faces thepowder. However, this part may also be non-self-adhesive.

Additional embodiments of such a principle of a multilayer product mayhave the following features:

A nonwoven layer may be replaced and/or supplemented by a film and/or afoam material. The materials may be laminated, in particular byproducing them by multilayer extrusion;

In particular, an outer layer may be based on cellulose or a similarmaterial. In particular, non-self-adhesive materials may be used, suchas those used in airlaid materials, tissue or paper, for example;

The nonwoven that is used may be finished with a hydrophilic orhydrophobic, oleophilic or oleophobic finish, e. g., by using therespective additive package or by application of substances afterproduction of the nonwoven or fiber. The nonwoven may be transparent orit may be designed with a color by pigmentation. The type of nonwovenmay be varied. For example, staple fibers, spunbonded nonwovens,meltblown nonwovens or other fiber or nonwoven materials may be used;

In addition to the polyolefins polypropylene and polyethylene andmixtures thereof which are preferred for use, other thermoplasticpolymers may also be used, in particular polyesters, polyamides[nylons], derivatives thereof, as copolymers or block copolymers. Inparticular, it has proven advantageous if bicomponent fibers ormulticomponent fibers, which have the corresponding desired propertiesor sealing capability of layers, are used;

The material used in the intermediate layer, in particular a powder, maybe applied over the entire area or only over a portion of the area. Inaddition, there is the possibility of providing this material in aprofiled form over a cross section in the longitudinal direction, thetransverse direction or in the vertical direction. This depends inparticular on the application of the subsequent finished product. Forexample, for hygiene products, the intermediate layer may be arranged insuch a way that the desired body contours and probable contact surfacesof fluids are adapted accordingly.

To support a bonding of the first layer and the second layer and/or oneof the two layers with a material of the intermediate layer, anadditional adhesive, in particular a hot-melt adhesive, may be appliedover all or part of the surface. The first layer and the second layerare preferably supplied as roll goods by means of unwinding.

The intermediate layer is arranged in particular as a freely portionablematerial layer between the first layer and the second layer according topredefinable geometries.

In addition, there is also the possibility of providing inlineproduction. For example, a nonwoven and/or film production installationis provided, with a corresponding feed for the material of theintermediate layer and/or the second layer being provided downstreamfrom this installation, with a subsequent material bonding station.

BRIEF DESCRIPTION OF THE DRAWINGS

Other advantageous embodiments and refinements are illustrated in thedrawings which follow. The features illustrated there can be combinedwith the refinement mentioned above but not described in greater detailhere. These figures show:

FIG. 1 a multilayer product with a first layer, an absorbentintermediate layer and a second layer;

FIG. 2 a second multilayer product;

FIG. 3 a first view of a first layer;

FIG. 4 a second view of a first layer;

FIG. 5 a first device for producing a multilayer product;

FIG. 6 a second device for producing a multilayer product;

FIG. 7 a a multilayer product that is not yet sealed;

FIG. 7 b the product shown in FIG. 7 a in a sealed form;

FIG. 8 a first arrangement of intermediate layers on a first layer;

FIG. 9 a second arrangement of intermediate layers on a first layer;

FIG. 10 a third device for producing a multilayer product, and FIG. 11 across section through a multilayer product.

MORE DETAILED DESCRIPTION

FIG. 1 shows a first multilayer product 1 with a first layer 2, anabsorbent intermediate layer 3 and a second layer 4. The first layer 2has a first material 5 and a second material 6. The second layer 4 has athird material 7 and a fourth material 8. The first layer 2 and thesecond layer 4 are both preferably nonwoven materials. At least one ofthe two materials 2, 4 may also contain a film and/or a foam. The firstmaterial 5 of the first layer 2 contains, for example, a polypropylene.It is preferably produced as a spunbonded nonwoven. The second material6 is polyethylene, for example. The third material 7 in turn preferablyalso contains polyethylene, but the fourth material 8 preferablycontains polypropylene. The absorbent intermediate layer 3, whichcontains particles 9, for example, according to this embodiment, isarranged between the first layer 2 and the second layer 4. The particlesare preferably held in place in the intermediate layer 3 at leastpartially by the polyethylene, which is softened by an increase intemperature. In addition, the polyethylene is heated to the extent thatthe additional material 6 of the first layer 2 is sealed to the thirdmaterial 7 of the second layer 4 and then escape of the particlesthrough this seal is prevented. In addition to particles 9,superabsorbent fibers, mixtures of superabsorbent fibers and particles,water-soluble fibers, in particular in a mixture with particles and/orpowder, e. g., of polyvinyl<BR>alcohol, e. g., cellulose or viscoseand/or other certain liquid-absorbing materials may also be arranged inthe intermediate layer 3. In addition, cosmetics, dyestuff, bloodcoagulants, blood anticoagulants, citric acid and/or electricconductors, either individually or in a mixture of the materialsmentioned above, may be present in the intermediate layer 3.

FIG. 2 shows a second multilayer product 10 in a cross-sectional view.The multilayer product 10 has a first layer 2 and a second layer 4. Thefirst layer 2 and the second layer 4 have a bicomponent fiber spunbondednonwoven facing inward, preferably containing polypropylene andpolyethylene. The arrangement of polypropylene and polyethylene ispreferably a side-by-side arrangement. The multilayer product 10 isheated after stacking the layers. Due to this heating, the materialwhich has a lower melting point is made to soften more rapidly. Inparticular, the heating temperature may result in the material havingthe lower melting point at least beginning to melt, while the othermaterial is still completely in its solid form. An intermediate layermaterial 11, which is arranged between the first layer 2 and the secondlayer 4 is accommodated by the partially melted material and is embeddedin it. According to another embodiment, instead of heating the entireproduct, only the intermediate layer may be heated in particular.Especially if the intermediate layer consists of particles or fibers,which are essentially less dependent on temperature than the surroundinglayers, such a procedure allows savings on energy costs. Theintermediate layer material is brought to a suitable temperature, e. g.,by a corresponding heating, e. g., infrared, hot air, heated rollers orinductive heating as well as steam heating, so that the intermediatematerial is bonded to the layers surrounding it. The intermediatematerial is heated, for example, when applying it to the first or secondlayer by a suitable applicator device according to a desired applicationand a desired application geometry.

FIG. 3 shows a first view of an intermediate layer material 11 which isapplied to a first layer 2. As indicated schematically, the intermediatelayer material 11 is applied over the entire area. The applicationitself is preferably performed in such a way that it is done without anyadditional cellulose. The intermediate layer material 11 is covered by asecond layer 4 in a working step which is not shown here, and it issealed at the sides because of the properties of the first layer 2 andthe second layer 4.

FIG. 4 shows another first layer 2 on which the intermediate layermaterial 11 is arranged. The arrangement of the intermediate layermaterial 11 follows a defined application geometry. For example, freezones 12 may be arranged between application areas of intermediate layermaterial 11. The free zones 12 may be arranged in the machine direction(MD) and in the transverse or crosswise direction (CD). If the materialis then passed through a calender after application of a second layer,the free zones 12 may later form sealing zones, by means of which thefirst layer 2 is bonded to an opposite second layer. Then the layers maybe cut through this sealing zone, to obtain individual absorbent pads inthis way.

FIG. 5 shows a first device 13 for producing a multilayer product 1. Thefirst layer 2 is supplied from a first drum 14 to an application station15 for the intermediate layer material 11. The second layer 4 is appliedto the intermediate layer material 11 from a second drum 16. In thedownstream heating station 17, the multilayer product 1 is heated. Thiscauses the second material (not shown in greater detail here) of thefirst layer 2 to be heated to the extent that it reaches at least itssoftening temperature and is bonded to the opposite second layer 4. Inaddition, heating the second material also yields the result that theintermediate layer material 11 is fixed in position by the secondmaterial. Bonding of the first layer 2 to the second layer 4 and/orbonding of the intermediate layer material 11 to at least the firstlayer 2 can thus be supported by applying a pressure to the layers. Thepressure can be exerted upstream from the heating station 17 and/ordownstream from the heating station 17 as well as during the heating.The heating station 17 may apply the required heat flow to themultilayer product over the full area or only part of the area. The heatflow may be introduced into the multilayer product by infrared heating,hot air, steam, for example, by heated rollers, by inductive heating orother measures. In addition, there is the possibility that theintermediate layer material 11 from the application station 15 may beapplied in a heated condition to the first layer 2, where the materialhaving the low melting point softens accordingly and sinks into itthere. In addition, the bonding of the first layer 2 to the second layer4 may also be accomplished subsequently through the heating station 17.With this first device 13, a windup station 18 is situated downstreamfrom the heating station 17. A cutting device (not shown here) may alsobe provided to divide the layers into sections, preferably in themachine direction and/or in the transverse direction.

FIG. 6 shows in a schematic diagram a second device 19 for producing amultilayer product 1. The second device 19 is an inline device. A firstspunbonded nonwoven 21 is deposited from a first spunbonded nonwovenbank 20 onto a revolving belt 22. From a second spunbonded nonwoven bank23, a material which at least partially has a different melting pointthan that of the first spunbonded nonwoven 21 is applied to this firstspunbonded nonwoven 21, which is not yet solidified. Preferably a secondspunbonded nonwoven 24 is applied. This second spunbonded nonwoven 24 isin particular a bicomponent fiber material, preferably made ofpolypropylene and polyethylene. The polypropylene and polyethylene maybe distributed in a fiber in a variety of ways. For example, there isthe possibility of providing a side-by-side arrangement. A core-sheatharrangement is also possible. Another arrangement provides for thepolypropylene and polyethylene to be arranged in segments at the surfaceand/or shortly in front of the surface of the fiber. The firstspunbonded nonwoven 21 and the second spunbonded nonwoven 24 are thencalendered by means of a thermobonding calender 25. Downstream from thethermobonding calender 25 is a second windup station 26. A secondapplication station 27 and a third spunbonded nonwoven bank 28 may bearranged between the second spunbonded nonwoven bank 23 and thethermobonding calender 25. The thermobonding calender 25 in particularis designed so that the layers are not only embossed and compressed, butinstead the multilayer product 1 is preferably also created with sealingsurfaces between the top and bottom layers. For example, the calendermay have corresponding elevations and/or recesses which have beenprovided around the circumference of one of the embossing calenderrolls. Preferably a cutting unit (not shown in detail here) is alsoarranged between the second windup station 26 and the thermobondingcalender 25, performing a separation cut, executed in the machinedirection in particular, between adjacent sealed areas. To do so, forexample, the intermediate layer material 11 coming from the secondapplication station 27 and inserted into the intermediate layer betweena top layer and a bottom layer is applied according to a predefinedpattern. In addition to the use of a spunbonded nonwoven, there is alsothe possibility of providing a staple fiber nonwoven and/or film, foamand/or meltblown nonwoven.

FIG. 7 a shows a multilayer material 29 that has not yet been sealed,and FIG. 7 b shows the multilayer material 29 after it has been sealed.The multilayer material 29 has a first outer layer 30 which is composedof two layers. The second outer layer 31 is a single layer. Theintermediate layer material 11 is arranged between the first outer layer30 an the second outer layer 31. According to the schematic diagram, theintermediate layer material 11 consists of functional particles. Theparticles are absorbent in particular. However, they may also have otherfunctions, e. g., releasing a scent. In addition, they may also beactivatable by certain influences. These influences may be, for example,heat, moisture, electric current, pressure or a pulse. The particlesthen enter a thermally activatable component 32 of the first outer layer30. As shown in FIG. 7 b, they are held together in this way. Through anappropriate application of pressure, the intermediate layer material 11may also at least partially enter the surface of the second outer layer31.

According to another embodiment not shown here, instead of the particlesillustrated in FIGS. 7 a and 7 b, fibers may also be used. Preferablyfibers as well as particles are active. Active means in particular thatthey are equipped with a special function. Another embodiment which isindependent of the former provides for a layer to be provided with anactive coating and/or for activatable components to be present in thiscoating. After drying and/or cross-linking with the layer, the coatingmay not be as elastic and/or flexible as the layer itself. By applying alayer arranged above it and then sealing, this prevents the coating orcomponents thereof from being able to pass through the layers or theseal if the coating is damaged or flakes off. For example, such acoating may be a superabsorbent coating.

FIG. 8 shows a first arrangement 33 of intermediate layers on a firstlayer 2. The intermediate layer materials 11 are arranged between afirst edge 34 and a second edge 35. These materials may be particlesand/or fibers. The goal is to utilize a production width of the firstlayer 2. To do so, the intermediate layer materials 11 may be depositedin strips which are continuous or, as shown, they may be deposited assubdivided geometric shapes. In addition, there may also be subsequentcutting planes 36 which are offset relative to one another. However, thecutting planes may also be aligned relative to one another so as toyield parallel cutting planes that are continuous in the machinedirection. Cutting planes that are also parallel but are offset relativeto one another may also be provided in the transverse direction. Thecutting planes are indicated with dotted lines as an example.

FIG. 9 shows another arrangement of cutting planes 36. In this case, thecutting planes do not run along a straight line but instead run along acurvature or they are at least partially round. For example, suchcutting planes 36 may be achieved by the fact that the first layer 2and/or the multilayer product 1 formed from them is passed through apunch. In addition, it is also possible for such a cutting plane to beproduced by a suitably designed calendar. The calendar has a roll, whichhas a suitably shaped surface geometry.

FIG. 10 shows a third device 37 for producing a multilayer product 1. Aspunbonded nonwoven 39, preferably consisting of polypropylene and/or acopolymer, is deposited on a second revolving belt 38. A bicomponentfiber spunbonded nonwoven 40 of polypropylene and polyethylene isdeposited on the spunbonded nonwoven 39. Then a powder-fiber mixture isapplied, forming a subsequent intermediate layer of the multilayerproduct 1. This is in turn followed by application of a secondbicomponent fiber spunbonded nonwoven 41 and a subsequent additionalspunbonded nonwoven 42. This multilayer material is then calendered,sealed and rolled up for further processing.

FIG. 11 shows a schematic diagram of a cross section of a multilayerproduct 1. The multilayer product 1 has a seal 43 between the firstlayer 2 and the second layer 4. The seal 43 is formed, for example, byheating the bicomponent fiber spunbonded nonwoven produced in FIG. 10 inthe subsequent calendering to the extent that the materials are fusedtogether and penetrate into one another mutually.

This leads to a mutual sealing which prevents the intermediate layermaterial 11 from escaping out of the absorbent intermediate layer 3.

1. A method of producing a multilayer product having at least one firstlayer, an absorbent intermediate layer and a second layer, whereby atleast the first layer has at least one first material and one secondmaterial, and the first layer and/or the second layer is at leastpartially liquid permeable, wherein a first material is used which has ahigher melting point than the second material; the second material isheated at least approximately to its melting point, and the first layerand the second layer are bonded by means of the heated second material,and wherein the intermediate layer comprises a powder which isimmobilized by the second material.
 2. The method according to claim 1,wherein a powder is applied to the second material to form the absorbentintermediate layer at least in part before the second material isheated, whereby the powder is glued at least partially to the secondmaterial.
 3. The method according to claim 1 wherein the second materialseals the intermediate layer at the sides.
 4. The method according toclaim 1, wherein the multilayer product is punched out of a continuouslysupplied sheet.
 5. The method according to claim 4, wherein multilayerproducts are punched out, their contours being arranged with an offsetrelative to one another.